FRITZ
At the close of the experiment
With one exception, all of the men were plainly having more proteid food than was necessary to maintain the body in nitrogen equilibrium, the plus nitrogen balance in most cases being fairly large. It is only necessary to remember that a gain to the body of 1 gram of nitrogen means a laying by of 6.25 grams of proteid, and with such a gain per day it is apparent that the men were really being supplied with an excess of proteid food. This view is supported by the fact that a later balance experiment, when considerably less proteid food was being given, still showed many of the men in a condition of plus balance, or with a minus balance so small as to indicate essentially nitrogen equilibrium. The following figures, being daily averages of a balance period about the first of April, may be offered in evidence:
| Nitrogen of Food. | Nitrogen of Urine. | Nitrogen of Excrement. | Nitrogen Balance. | |
|---|---|---|---|---|
| grams | grams | grams | grams | |
| Broyles | 8.66 | 6.63 | 1.87 | +0.16 |
| Fritz | 8.13 | 5.77 | 1.63 | +0.73 |
| Loewenthal | 8.51 | 6.51 | 2.02 | –0.02 |
| Steltz | 8.32 | 6.50 | 1.88 | –0.06 |
| Cohn | 8.29 | 6.25 | 1.55 | +0.49 |
| Morris | 8.45 | 6.49 | 2.27 | –0.31 |
| Oakman | 8.62 | 7.04 | 1.87 | –0.29 |
A daily intake of 8.5 grams of nitrogen means the consumption of 53 grams of proteid. Under these conditions of diet, the average daily amount of nitrogen metabolized was 6.45 grams, corresponding to 40.3 grams of proteid. The men were practically in a condition of nitrogen equilibrium, so that we are apparently justified in the general statement that the simple dietary followed with these men during the six months’ experiment, and which was accompanied by an average daily metabolism, after the first three weeks, of 7.8 grams of nitrogen, was certainly sufficient to maintain both body-weight and nitrogen equilibrium. Lastly, emphasis may be laid upon the fact that these values for nitrogen do not necessarily represent the minimal proteid requirement of the human body, since it is a well-established physiological principle that by increase of non-nitrogenous food the rate of proteid katabolism can always be further diminished; a principle which is plainly in harmony with the view that a high rate of proteid exchange is not a necessary requisite for the welfare of the body.
The experimental results presented afford very convincing proof that so far as body-weight and nitrogen equilibrium are concerned, the needs of the body are fully met by a consumption of proteid food far below the fixed dietary standards, and still further below the amounts called for by the recorded habits of mankind. General health is equally well maintained, and with suggestions of improvement that are frequently so marked as to challenge attention. Most conspicuous, however, though something that was entirely unlooked for, was the effect observed on the muscular strength of the various subjects. When the experiments were planned, it was deemed important to arrange for careful quantitative tests of the more conspicuous muscles of the body, with a view to measuring any loss of strength that might occur from the proposed reduction in proteid food. The thought that prompted this action was a result of the latent feeling that somehow muscular strength must be dependent more or less upon the proteid constituents of the muscles, and that consequently the cutting down of proteid food would inevitably be felt in some degree. The most that could be hoped for was that muscle tone and muscular strength might be maintained unimpaired. Hence, we were at first quite astonished at what was actually observed.
With the soldier detail, fifteen distinct strength tests were made with each man during the six months’ period, by means of appropriate dynamometer tests applied to the muscles of the back, legs, chest, upper arms, and forearms, reinforced by quarter-mile run, vault, and ladder tests, etc. The so-called “total strength” of the man was computed by multiplying the weight of the body by the number of times the subject was able to push up (strength of triceps muscles) and pull up (strength of biceps muscles) his body while upon the parallel bars, to this product being added the strength (dynamometer tests) of hands, legs, back, and chest. It should be added that all of these tests were made quite independently in the university gymnasium by the medical assistants and others in charge of the work there. It will suffice for our purpose to give here the strength tests of the various members of the soldier detail at the beginning and close of the experiment.
TOTAL STRENGTH
| October. | April. | |
|---|---|---|
| Broyles | 2560 | 5530 |
| Coffman | 2835 | 6269 |
| Cohn | 2210 | 4002 |
| Fritz | 2504 | 5178 |
| Henderson | 2970 | 4598 |
| Loewenthal | 2463 | 5277 |
| Morris | 2543 | 4869 |
| Oakman | 3445 | 5055 |
| Sliney | 3245 | 5307 |
| Steltz | 2838 | 4581 |
| Zooman | 3070 | 5457 |
Without exception, we note with all of the men a phenomenal gain in strength, which demands explanation. Was it all due to the change in diet? Probably not, for these men at the beginning of the experiment were untrained, and it is not to be assumed that months of practical work in the gymnasium would not result in a certain amount of physical development, with corresponding gain in muscular skill and power. Putting this question aside for the moment, however, it is surely proper to emphasize this fact; viz., that although the men for a period of five months were restricted to a daily diet containing only one-third to one-half the amount of proteid food they had been accustomed to, there was no loss of physical strength; no indication of any physical deterioration that could be detected. In other words, the men were certainly not being weakened by the lowered intake of proteid food. This is in harmony with the principle, already discussed, that the energy of muscle work comes primarily from the breaking down of non-nitrogenous material, and consequently a diminished intake of proteid food can have no inhibitory effect, provided, of course, there is an adequate amount of proteid ingested to satisfy the endogenous requirements of the tissues.
On the other hand, recalling the large number of nitrogenous cleavage products which result from the breaking down of proteid material, we can conceive of an exaggerated exogenous proteid katabolism which may flood the tissues and the surrounding lymph with a variety of nitrogenous waste products, having an inhibitory effect upon the muscle fibres themselves, or upon the peripheral endings of the motor nerves, by which the muscles are prevented, directly or indirectly, from working at their highest degree of efficiency. This being true, a reduction of the exogenous katabolism to a level more nearly commensurate with the real needs of the body might result in a marked increase in the functional power of the tissue. However this may be, the fact remains that all of the subjects showed this great gain in strength; and furthermore, there was a noticeable gain in self-reliance and courage in their athletic work, both of which are likewise indicative of an improved condition of the body. How far these improvements are attributable to training and to the more regular life the men were leading, and how far to the change in diet, cannot be definitely determined. We may venture the opinion, however, for reasons to be made clear shortly, that the change in diet was in a measure at least responsible for the increased efficiency. As the writer has already expressed it, there must be enough food to make good the daily waste of tissue, enough food to furnish the energy of muscular contraction, but any surplus over and above what is necessary to supply these needs is not only a waste, but may prove an incubus, retarding the smooth working of the machinery and detracting from the power of the organism to do its best work.